Rotary positioner

ABSTRACT

A pneumatically operated shaft positioner which has a C-shaped chamber with a rotary vane member responding to differential pressure conditions caused by opening an exhaust port around the periphery of the chamber.

United States Patent Ragard v [54] ROTARY POSITIONER [72] Inventor:Phillip A. Regard, Binghamton,

NY. I

[73] Assignee: Universal Instruments Corporation,

v Binghamton, N.Y.

[22] Filed: Nov. 9, 1970 [21] App1.No.: 87,861

[52] US. Cl ..92/l21, 19/357 [51] Int. Cl. ..F01c 9/00 [58] Field ofSearch ...92/121, 122; 91/408, 409, 357

[56] References Cited UNITED STATES PATENTS 2,825,307 3/1958 Enyeart..91l357 3,094,041 6/1963 Wagner ..92/ 122 2,890,889 6/1959 Work "912/122 3,411,413 11/1968 MacNeill ..91/357 51 Oct. 10,1972

2,404,262 7/ 1946 Whitfield ..92/121 2,557,912 6/1951 Lane ..92/1223,063 ,422 1 H1962 Gregowski et a1. ..92/121 2,915,044 12/1959 Nelson..92/ 121 2,902,009 9/ 1959 Ludwig ..92/121 UX FOREIGN PATENTS ORAPPLICATIONS 1,928,749 12/1970 Germany ..91l357 PrimaryExaminerMartin P.Schwadron Assistant Examiner-R. I-I. Lazarus Attorney-Fidelman, Wolffe &Leitner [57] ABSTRACT A pneumatically operated shaft positioner whichhas a C-shaped chamber with a rotary vane member responding todifferential pressure conditions caused by opening an exhaust portaround the periphery of the chamber.

7 Claims, 3 Drawing Figures PME'NTEU um 10 um INVENTOR PHILLIP A. RAGARDROTARY POSITIONER This invention relates to an automatic positioningdevice which may be adjusted to position a shaft at any predetermineddegree of rotation.

One of the requirements arising in various industries is the need to beable to rotate a shaft carrying a tool, instrument, etc., to a desiredangular position positively.

The usual approaches to this problem have involved gearing arrangementsor directly coupled motors with angular stop means. Numerous problemshave been encountered using these arrangements. One problem has been theinability to achieve a positive angular position due to gear tolerancesand wear. Another problem has been oscillation of the shaft once itreaches the predetermined position due to play and bounce in themechanical arrangements. While some pneumatic mechanisms have beentried, they have been unsuccessful.

This invention is directed to a pneumatic rotary vane shaft positioner.The chamber is positioned on the shaft and externally fixed and a vaneis securely attached to the shaft for rotary movement within thechamber. A fixed wall is positioned within the chamber also and, withthe vane, divides the chamber into two subchambers. Air from one sourceis admitted into the two subchambers by ports that can be located in thefixed wall or adjacent thereto.

- A series of additional ports are located around the periphery of thechamber. The size of the ports is slightly larger than the width of thevane. The ports are adapted to be opened and closed externally, one at atime. When air under pressure is admitted into the device and one of theperipheral ports is opened, the vane will rotate until it centerson'that port, carrying with it the shaft. Since the port is slightlywider than the vane, willbe allowed to escape and no oscillation of thevane occurs. The air pressure in the subchambers will be equal at thispoint.

When it is desired to rotate the shaft to a new angular position, thefirst peripheral port is closed and a second one opened. Again, thevaneand shaft will rotate until it centers on the second port. I

Accordingly, it is one object of this invention to provide apneumatically controlled shaft positioning mechanism.

It is a further object of this invention to provide a shaft positioningapparatus having a plurality of angular adjustment positions.

It is a still further object of this invention to provide a positiveaction shaft positioning mechanism with only one moving part.

A further object of this invention is to provide a pneumatic positioningmechanism which will angularly position shafts without any oscillationof the shaft.

These and other objects of this invention will become apparent whentaken with reference to the accompanying specification and drawings inwhich:

FIG. 1 is a perspective view, partially broken away, showing theinternal chamber and vane configuration of the positioning mechanism;

FIG. 2 is a plan view of the mechanism comprising this invention;

FIG. 3 is a cross sectional view of the positioning mechanism takenalong line 303 of FIG. 2.

tapped bores 107 are aligned to receive machine screws 108.

Plates 102 and 104 are centrally bored at 109 and I 112, respectively,which holes are internally counterbored at 110 and 113 respectively.These counterbored portions receive bushings 111 and 114 which engageshaft 115, adapted to rotate-within housing 101 on bushings.

Mounted on shaft 115 between plates 102 and 104 is a cylindrical vanesupport collar 116. It has flat end portions 117 and 118 which tightlyengage the internal planar faces of plated 102 and 104.

Secured in any suitable fashion, such as by welding to collar 116 isvane 120 which has flat parallel sides 121 and 122 and an arcuate edgeportion 123 which, together with the internal configuration of chamber103, forms a seal making for two variable size subchambers, withinchamber 103 in conjunction with a preshaped wall member 124.

Member 124 has radial flat sides 125 and 126 and arcuate outer end 127.It is tapped at 129 to receive the end of a machine screw 129 whichpasses through hole 131 in housing 101 (FIG. 3) and has a countersunkhead portion 130. Screw 129 holds it in place to allow collar 116 torotate until either side 121 or 122 of vane 120 engages a correspondingside 125 or 126.

There are two air inlet holes 132 and 133 provided in plate 104 adjacentand slightly overlapping sides 125 and 126 of member 124. The holesoverlap the sides, as shown in FIG. 2, for the purpose of insuring thatvane 120 moves in case it is in the position of abutting member 124. Afitting (FIG. 1) is used to connect inlet tubing 134 to said holes.

Around the periphery of housing 101 are a series of bores, such as 135in FIG. 3, which receive exhaust port fittings such as 137 and 140 (FIG.3).

Fitting 137, as shown in cross section in FIG. 3, has a threaded portion138, a flange portion 136, an intermediate portion 138 and a reduceddiameter passage 139. The exhaust fittings may also include a sealinggasket such as 142 which sits under flange 141 of fitting 140.

Plate 104 has lapped holes such as 144 and 145 therein for the, purpose"of securing assembly 100 against rotation with shaft 1 15.

Collar 1 16 is bored at 146 which aligns with hole 148 in shaft 1 15 toreceive a press-fitted locking pin 147.

Referring again to inlet ports 132 and 133, it is obvious that they maybe provided within member 124 in the general shape of a Y-port.

The operation of the apparatus is simple. Air from the same source,i.e., at the same pressure, is admitted into chamber 103. A particularexhaust valve (any number can be employed) is opened, e. g., port 137Since port 137 will be in one of the two subchambers created by vane 120and member 124, the inlet air coming into that subchamber will exitthrough port 137. Since this will produce less pressure in thissubchamber than in the other subchamber, the vane will be forced in thedirection of lower pressure. It will continue moving until it reachesport 137. Since the diameter of bore 135 is slightly wider than thearcuate end face 123, the vane will center on the port and air will leakout on either side of the vane 120.

When it is desired to change shaft position, port 137 is closed andanother opened. Vane 120 again moves in the same manner.

The assembly 100 can be constructed of any suitable material, such assteel, aluminum, plastic, etc. and may be as large as desired.Naturally, the larger the shaft and the heavier the load, the more airpressure that will be needed.

While only one embodiment of the rotary pneumatic position has beenshown and described, it will be obvious to those of ordinary skill inthe art that many changes and modifications can be made withoutdeparting from the scope of the appended claims.

What is claimed is:

1. A pneumatically operated shaft positioner comprising a housing, acylindrical chamber within said housing, a rotatable vane means withinsaid chamber, shaft means externally of said housing and in operativerelationship with said rotatable vane means, a partition means in saidchamber which, with said vane means, divides said chamber into twosubchambers which vary in volume depending on the position of the vanemeans, air inlet means adjacent said partition means and adapted toadmit air under equal pressure to either side of said partition means,said air inlet means being sufficiently large to simultaneously overlapa portion of said partition means and entirely overlap said rotable vanemeans when said rotable vane means is adjacent said partition means inorder to insure proper movement of said vane from said partition means,and at least one pressure exit port means of a dimension larger than thewidth of said vane means so as to allow air to escape said subchamberswhen said vane means is positioned adjacent said port means by the airpressures in said subchambers.

2. A shaft positioner as in claim 1 wherein there are a series of exitport means in said chamber.

3. A shaft positioner as in claim 2 wherein said series of exit portmeans are located on the inner peripheral wall of said chamber.

4. A shaft positioner as in claim 2 and including means to open one exitport means and close the other exit port means.

5. A shaft positioner as in claim 1 wherein said chamber means iscylindrical in volume, said shaft means passing through said chambermeans and coaxial therewith, a collar on said shaft means, said collarhaving a vertical height substantially the same as the height of saidcylindrical chamber and extending from said collar substantially to theinner periphery of said chamber, said partition means being fixed inposition.

6. A shaft positioner as in claim 5 wherein there are a series of exitport means located on the inner peripheral wall of said chamber, eachexit port being of a circular configuration, and means to selectivelyopen said exit ports to position said shaft in predetermined angularpositions.

7. A shaft positioner as in claim 5 wherein said air inlet meanscomprises two ports located in said housing ad acent to and overlappingsaid partition means; an

said ports are sufficiently large to allow air to escape saidsubchambers when said vane means is positioned adjacent said air inletports.

1. A pneumatically operated shaft positioner comprising a housing, acylindrical chamber within said housing, a rotatable vane means withinsaid chamber, shaft means externally of said housing and in operativerelationship with said rotatable vane means, a partition means in saidchamber which, with said vane means, divides said chamber into twosubchambers which vary in volume depending on the position of the vanemeans, air inlet means adjacent said partition means and adapted toadmit air under equal pressure to either side of said partition means,said air inlet means being sufficiently large to simultaneously overlapa portion of said partition means and entirely overlap said rotable vanemeans when said rotable vane means is adjacent said partition means inorder to insure proper movement of said vane from said partition means,and at least one pressure exit port means of a dimension larger than thewidth of said vane means so as to allow air to escape said subchamberswhen said vane means is positioned adjacent said port means by the airpressures in said subchambers.
 2. A shaft positioner as in claim 1wherein there are a series of exit port means in said chamber.
 3. Ashaft positioner as in claim 2 wherein said series of exit port meansare located on the inner peripheral wall of said chamber.
 4. A shaftpositioner as in claim 2 and including means to open one exit port meansand close the other exit port means.
 5. A shaft positioner as in claim 1wherein said chamber means is cylindrical in volume, said shaft meanspassing through said chamber means and coaxial therewith, a collar onsaid shaft means, said collar having a vertical height substantially thesame as the height of said cylindrical chamber and extending from saidcollar substantially to the inner periphery of said chamber, saidpartition means being fixed in position.
 6. A shaft positioner as inclaim 5 wherein there are a series of exit port means located on theinner peripheral wall of said chamber, each exit port being of acircular configuration, and means to selectively open said exit ports toposition said shaft in predetermined angular positions.
 7. A shaftpositioner as in claim 5 wherein said air inlet means comprises twoports located in said housing adjacent to and overlapping said partitionmeans; and said ports are sufficiently large to allow air to escape saidsubchambers when said vane means is positioned adjacent said air inletports.